WASHINGTON — The U.S. government and 48 states and districts sued Facebook Wednesday, accusing it of abusing its market power in social networking to crush smaller competitors and seeking remedies that could include a forced spinoff of the social network’s Instagram and WhatsApp messaging services.The landmark antitrust lawsuits, announced by the Federal Trade Commission and New York Attorney General Letitia James, mark the second major government offensive this year against seemingly untouchable tech behemoths. The …